[directorytree] Disable hover and cursor effects when inactive

If the pointer is down anywhere in the app, hovering over the tree Tab
items shows their :hover and cursor effects even though these Tabs are
not interactive: disable these effects so the Tabs look inert.

So what about Pressed state for a Tab? No spec for this: reuse the Tab
Hover state color for Pressed state for now (--google-grey-100).

No-try: true
Bug: 992819, 1062902
Change-Id: I571b252dbe4ddc3050284af505ae3432ad5521d4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2134088Reviewed-by: Noel Gordon <noel@chromium.org>
Reviewed-by: Alex Danilo <adanilo@chromium.org>
Commit-Queue: Noel Gordon <noel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#756105}

ui/file_manager/file_manager/foreground/css/file_manager.css

@@ -309,6 +309,20 @@ html:not(.col-resize) #directory-tree
   background-color: var(--google-grey-100);
 }
 
+html.pointer-active #directory-tree
+    .tree-row:not([active]):not([selected]) > .file-row:active {
+  background-color: var(--google-grey-100);
+}
+
+html.pointer-active #directory-tree
+    .tree-row:not([active]):not([selected]):hover > .file-row:not(:active) {
+  background-color: unset;
+}
+
+html.pointer-active #directory-tree :not(:active) {
+  cursor: default;
+}
+
 html.focus-outline-visible #directory-tree:focus .tree-row[selected] > .file-row {
   border: 1px solid var(--google-blue-600);
 }